Neodymium, 15 mm in diameter, 3 mm in height. Poles as shown in the attached image.

The image didn't appear in your post , but I'm familiar with the type , the hole is often countersunk , allowing the magnet to be screwed onto wood ..

The pole is on the face , works best when screwed onto a flat wood surface , you can put many to increase pull power , space them apart with about 10mm between each one ..

Be careful they are easily damaged , the surface is easily chipped if it pulls a metal object violently to itself . to prevent this you may want to put a thin rubber/silicon layer or mat about 1mm thick on top of the magnets. Or removable material , cloth might do, this makes it easy to remove any small items attracted to the magnets, you simply take the cloth off.